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From: Pierre-Marie de Rodat <pmderodat@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-4541] [Ada] Warning on nonmatching subtypes in fully conforming subprogram specs and bodies Date: Wed, 20 Oct 2021 10:18:09 +0000 (GMT) [thread overview] Message-ID: <20211020101809.A7711385803B@sourceware.org> (raw) https://gcc.gnu.org/g:749e01a5f310f2c4327f030d425aa6e23afbbbd5 commit r12-4541-g749e01a5f310f2c4327f030d425aa6e23afbbbd5 Author: Gary Dismukes <dismukes@adacore.com> Date: Fri Oct 8 17:57:37 2021 -0400 [Ada] Warning on nonmatching subtypes in fully conforming subprogram specs and bodies gcc/ada/ * sem_ch6.adb: Add with and use of Warnsw. (Check_Conformance): Report a warning when subtypes or designated subtypes of formal parameters or result subtypes denote different declarations between the spec and body of the (Subprogram_Subtypes_Have_Same_Declaration): New function nested within Check_Conformance that determines whether two subtype entities referenced in a subprogram come from the same declaration. Returns True immediately if the subprogram is in a generic instantiation, or the subprogram is marked Is_Internal or is declared in an internal (GNAT library) unit, or GNAT_Mode is enabled, otherwise compares the nonlimited views of the entities (or their designated subtypes' nonlimited views in the anonymous access cases). (Nonlimited_View_Of_Subtype): New function nested within function Subprogram_Subtypes_Have_Same_Declaration that returns Non_Limited_View of a type or subtype that is an incomplete or class-wide type that comes from a limited of a package (From_Limited_With is True for the entity), or returns Full_View when the nonlimited view is an incomplete type. Otherwise returns the entity passed in. * warnsw.ads (Warn_On_Pedantic_Checks): New warning flag. (type Warning_Record): New component Warn_On_Pedantic_Checks. * warnsw.adb (All_Warnings): Set Warn_On_Pedantic_Checks from parameter Setting. (Restore_Warnings): Restore the value of the Warn_On_Pedantic_Checks flag. (Save_Warnings): Save the value of the Warn_On_Pedantic_Checks flag. (Set_Underscore_Warning_Switch): Add settings of the Warn_On_Pedantic flag according to the switch ("-gnatw_p" vs. "-gnatw_P"). * doc/gnat_ugn/building_executable_programs_with_gnat.rst: Add documentation of new switches -gnatw_p and -gnatw_P (warnings for pedantic checks). * gnat_ugn.texi: Regenerate. * usage.adb: Add Warn_On_Pedantic_Checks. Diff: --- .../building_executable_programs_with_gnat.rst | 19 ++++ gcc/ada/gnat_ugn.texi | 30 +++++- gcc/ada/sem_ch6.adb | 116 +++++++++++++++++++++ gcc/ada/usage.adb | 2 + gcc/ada/warnsw.adb | 11 ++ gcc/ada/warnsw.ads | 8 ++ 6 files changed, 185 insertions(+), 1 deletion(-) diff --git a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst index 67fd1301a67..48b7623c1de 100644 --- a/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst +++ b/gcc/ada/doc/gnat_ugn/building_executable_programs_with_gnat.rst @@ -3582,6 +3582,25 @@ of the pragma in the :title:`GNAT_Reference_manual`). ordering. +.. index:: -gnatw_p (gcc) + +:switch:`-gnatw_p` + *Activate warnings for pedantic checks.* + + This switch activates warnings for the failure of certain pedantic checks. + The only case currently supported is a check that the subtype_marks given + for corresponding formal parameter and function results in a subprogram + declaration and its body denote the same subtype declaration. The default + is that such warnings are not given. + +.. index:: -gnatw_P (gcc) + +:switch:`-gnatw_P` + *Suppress warnings for pedantic checks.* + + This switch suppresses warnings on violations of pedantic checks. + + .. index:: -gnatwq (gcc) .. index:: Parentheses, warnings diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi index 28f2f19290a..cae1fadc464 100644 --- a/gcc/ada/gnat_ugn.texi +++ b/gcc/ada/gnat_ugn.texi @@ -21,7 +21,7 @@ @copying @quotation -GNAT User's Guide for Native Platforms , Sep 28, 2021 +GNAT User's Guide for Native Platforms , Oct 19, 2021 AdaCore @@ -11800,6 +11800,34 @@ This switch suppresses warnings on cases of suspicious parameter ordering. @end table +@geindex -gnatw_p (gcc) + + +@table @asis + +@item @code{-gnatw_p} + +@emph{Activate warnings for pedantic checks.} + +This switch activates warnings for the failure of certain pedantic checks. +The only case currently supported is a check that the subtype_marks given +for corresponding formal parameter and function results in a subprogram +declaration and its body denote the same subtype declaration. The default +is that such warnings are not given. +@end table + +@geindex -gnatw_P (gcc) + + +@table @asis + +@item @code{-gnatw_P} + +@emph{Suppress warnings for pedantic checks.} + +This switch suppresses warnings on violations of pedantic checks. +@end table + @geindex -gnatwq (gcc) @geindex Parentheses diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb index e32c4ad504c..a316214f223 100644 --- a/gcc/ada/sem_ch6.adb +++ b/gcc/ada/sem_ch6.adb @@ -90,6 +90,7 @@ with Tbuild; use Tbuild; with Uintp; use Uintp; with Urealp; use Urealp; with Validsw; use Validsw; +with Warnsw; use Warnsw; package body Sem_Ch6 is @@ -5962,6 +5963,17 @@ package body Sem_Ch6 is -- True if the null exclusions of two formals of anonymous access type -- match. + function Subprogram_Subtypes_Have_Same_Declaration + (Subp : Entity_Id; + Decl_Subtype : Entity_Id; + Body_Subtype : Entity_Id) return Boolean; + -- Checks whether corresponding subtypes named within a subprogram + -- declaration and body originate from the same declaration, and returns + -- True when they do. In the case of anonymous access-to-object types, + -- checks the designated types. Also returns True when GNAT_Mode is + -- enabled, or when the subprogram is marked Is_Internal or occurs + -- within a generic instantiation or internal unit (GNAT library unit). + ----------------------- -- Conformance_Error -- ----------------------- @@ -6094,6 +6106,86 @@ package body Sem_Ch6 is end if; end Null_Exclusions_Match; + function Subprogram_Subtypes_Have_Same_Declaration + (Subp : Entity_Id; + Decl_Subtype : Entity_Id; + Body_Subtype : Entity_Id) return Boolean + is + + function Nonlimited_View_Of_Subtype + (Subt : Entity_Id) return Entity_Id; + -- Returns the nonlimited view of a type or subtype that is an + -- incomplete or class-wide type that comes from a limited view of + -- a package (From_Limited_With is True for the entity), or the + -- full view when the subtype is an incomplete type. Otherwise + -- returns the entity passed in. + + function Nonlimited_View_Of_Subtype + (Subt : Entity_Id) return Entity_Id + is + Subt_Temp : Entity_Id := Subt; + begin + if Ekind (Subt) in Incomplete_Kind | E_Class_Wide_Type + and then From_Limited_With (Subt) + then + Subt_Temp := Non_Limited_View (Subt); + end if; + + -- If the subtype is incomplete, return full view if present + -- (and accounts for the case where a type from a limited view + -- is itself an incomplete type). + + if Ekind (Subt_Temp) in Incomplete_Kind + and then Present (Full_View (Subt_Temp)) + then + Subt_Temp := Full_View (Subt_Temp); + end if; + + return Subt_Temp; + end Nonlimited_View_Of_Subtype; + + -- Start of processing for Subprogram_Subtypes_Have_Same_Declaration + + begin + if not In_Instance + and then not In_Internal_Unit (Subp) + and then not Is_Internal (Subp) + and then not GNAT_Mode + and then + Ekind (Etype (Decl_Subtype)) not in Access_Subprogram_Kind + then + if Ekind (Etype (Decl_Subtype)) = E_Anonymous_Access_Type then + if Nonlimited_View_Of_Subtype (Designated_Type (Decl_Subtype)) + /= Nonlimited_View_Of_Subtype (Designated_Type (Body_Subtype)) + then + return False; + end if; + + elsif Nonlimited_View_Of_Subtype (Decl_Subtype) + /= Nonlimited_View_Of_Subtype (Body_Subtype) + then + -- Avoid returning False (and a false-positive warning) for + -- the case of "not null" itypes, which will appear to be + -- different subtypes even when the subtype_marks denote + -- the same subtype. + + if Ekind (Decl_Subtype) = E_Access_Subtype + and then Ekind (Body_Subtype) = E_Access_Subtype + and then Is_Itype (Body_Subtype) + and then Can_Never_Be_Null (Body_Subtype) + and then Etype (Decl_Subtype) = Etype (Body_Subtype) + then + return True; + + else + return False; + end if; + end if; + end if; + + return True; + end Subprogram_Subtypes_Have_Same_Declaration; + -- Local Variables Old_Type : constant Entity_Id := Etype (Old_Id); @@ -6147,6 +6239,18 @@ package body Sem_Ch6 is end if; return; + + -- If the result subtypes conform and pedantic checks are enabled, + -- check to see whether the subtypes originate from different + -- declarations, and issue a warning when they do. + + elsif Ctype = Fully_Conformant + and then Warn_On_Pedantic_Checks + and then not Subprogram_Subtypes_Have_Same_Declaration + (Old_Id, Old_Type, New_Type) + then + Error_Msg_N ("result subtypes conform but come from different " + & "declarations??", New_Id); end if; -- Ada 2005 (AI-231): In case of anonymous access types check the @@ -6343,6 +6447,18 @@ package body Sem_Ch6 is end if; return; + + -- If the formals' subtypes conform and pedantic checks are enabled, + -- check to see whether the subtypes originate from different + -- declarations, and issue a warning when they do. + + elsif Ctype = Fully_Conformant + and then Warn_On_Pedantic_Checks + and then not Subprogram_Subtypes_Have_Same_Declaration + (Old_Id, Old_Formal_Base, New_Formal_Base) + then + Error_Msg_N ("formal subtypes conform but come from " + & "different declarations??", New_Formal); end if; -- For mode conformance, mode must match diff --git a/gcc/ada/usage.adb b/gcc/ada/usage.adb index bca35271ae6..207303bed0e 100644 --- a/gcc/ada/usage.adb +++ b/gcc/ada/usage.adb @@ -557,6 +557,8 @@ begin "order"); Write_Line (" .P* turn off warnings for suspicious parameter " & "order"); + Write_Line (" _p turn on warnings for pedantic checks"); + Write_Line (" _P turn off warnings for pedantic checks"); Write_Line (" q*+ turn on warnings for questionable " & "missing parenthesis"); Write_Line (" Q turn off warnings for questionable " & diff --git a/gcc/ada/warnsw.adb b/gcc/ada/warnsw.adb index 912ceea4786..149e2fdbe29 100644 --- a/gcc/ada/warnsw.adb +++ b/gcc/ada/warnsw.adb @@ -76,6 +76,7 @@ package body Warnsw is Warn_On_Overlap := Setting; Warn_On_Overridden_Size := Setting; Warn_On_Parameter_Order := Setting; + Warn_On_Pedantic_Checks := Setting; Warn_On_Questionable_Layout := Setting; Warn_On_Questionable_Missing_Parens := Setting; Warn_On_Record_Holes := Setting; @@ -172,6 +173,8 @@ package body Warnsw is W.Warn_On_Overridden_Size; Warn_On_Parameter_Order := W.Warn_On_Parameter_Order; + Warn_On_Pedantic_Checks := + W.Warn_On_Pedantic_Checks; Warn_On_Questionable_Layout := W.Warn_On_Questionable_Layout; Warn_On_Questionable_Missing_Parens := @@ -284,6 +287,8 @@ package body Warnsw is Warn_On_Overridden_Size; W.Warn_On_Parameter_Order := Warn_On_Parameter_Order; + W.Warn_On_Pedantic_Checks := + Warn_On_Pedantic_Checks; W.Warn_On_Questionable_Layout := Warn_On_Questionable_Layout; W.Warn_On_Questionable_Missing_Parens := @@ -505,6 +510,12 @@ package body Warnsw is when 'C' => Warn_On_Unknown_Compile_Time_Warning := False; + when 'p' => + Warn_On_Pedantic_Checks := True; + + when 'P' => + Warn_On_Pedantic_Checks := False; + when 'r' => Warn_On_Component_Order := True; diff --git a/gcc/ada/warnsw.ads b/gcc/ada/warnsw.ads index 340a7529445..611353835ea 100644 --- a/gcc/ada/warnsw.ads +++ b/gcc/ada/warnsw.ads @@ -58,6 +58,13 @@ package Warnsw is -- set with an explicit size clause. Off by default, modified by use of -- -gnatw.s/.S (but not -gnatwa). + Warn_On_Pedantic_Checks : Boolean := False; + -- Warn for violation of miscellaneous pedantic rules (such as when the + -- subtype of a formal parameter given in a subprogram body's specification + -- comes from a different subtype declaration that the subtype of the + -- formal in the subprogram declaration). Off by default, and set by + -- -gnatw_p (but not -gnatwa). + Warn_On_Questionable_Layout : Boolean := False; -- Warn when default layout of a record type is questionable for run-time -- efficiency reasons and would be improved by reordering the components. @@ -128,6 +135,7 @@ package Warnsw is Warn_On_Overlap : Boolean; Warn_On_Overridden_Size : Boolean; Warn_On_Parameter_Order : Boolean; + Warn_On_Pedantic_Checks : Boolean; Warn_On_Questionable_Layout : Boolean; Warn_On_Questionable_Missing_Parens : Boolean; Warn_On_Record_Holes : Boolean;
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